Assertion-Reason: Dimensions of Strain and Young’s Modulus – Rankers Physics
Topic: Solid and Fluids
Subtopic: Solids

Assertion-Reason: Dimensions of Strain and Young’s Modulus

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Strain is a dimensionless quantity.
Reason R: Unit of Young’s modulus is same as that of stress.
In the light of the above statements, choose the correct answer from the option given below.
Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not the correct explanation of A
A is true but R is false
A is false but R is true

Solution:

Strain is indeed dimensionless since it's the ratio of two similar physical quantities (change in dimension over original dimension). The unit of Young's modulus is indeed identical to stress (both are \(\text{N/m}^2\)). However, the second statement is not the reason for the first.

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